MODULE SQLitePrepareTail;
(* sqlite3_prepare_v3: prepare one statement and reuse its tail. *)

FROM SYSTEM IMPORT ADDRESS;
FROM CStr IMPORT Copy;
FROM SQLite IMPORT
  DbHandle, StmtHandle,
  SQLiteOk, SQLiteRow, SQLiteDone,
  SQLiteOpenReadWrite, SQLiteOpenCreate, SQLiteOpenMemory,
  SQLitePreparePersistent,
  sqlite3_open_v2, sqlite3_close,
  sqlite3_prepare_v3, sqlite3_step, sqlite3_column_int,
  sqlite3_finalize;

VAR
  ExitCode : INTEGER;
  db : DbHandle;
  stmt : StmtHandle;
  tail, tail2 : ADDRESS;
  rc : INTEGER;
  ok : BOOLEAN;
  buf : ARRAY [0..127] OF CHAR;

PROCEDURE SameText (a, b : ARRAY OF CHAR) : BOOLEAN;
VAR
  i : INTEGER;
BEGIN
  i := 0;
  WHILE (a[i] # CHR(0)) AND (a[i] = b[i]) DO i := i + 1 END;
  RETURN (a[i] = CHR(0)) AND (b[i] = CHR(0))
END SameText;

BEGIN
  ExitCode := 1;
  db := NIL; stmt := NIL; tail := NIL; tail2 := NIL; ok := FALSE;

  IF (sqlite3_open_v2(":memory:", db,
        SQLiteOpenReadWrite + SQLiteOpenCreate + SQLiteOpenMemory,
        NIL) = SQLiteOk) AND (db # NIL) THEN
    rc := sqlite3_prepare_v3(db, "SELECT 1; SELECT 2;", -1,
                             SQLitePreparePersistent, stmt, tail);
    ok := (rc = SQLiteOk) AND (stmt # NIL) AND (tail # NIL);
    IF ok THEN
      IF Copy(tail, buf) = 0 THEN
        ok := FALSE
      ELSIF NOT SameText(buf, " SELECT 2;") THEN
        ok := FALSE
      END
    END;
    IF ok THEN ok := sqlite3_step(stmt) = SQLiteRow END;
    IF ok THEN ok := sqlite3_column_int(stmt, 0) = 1 END;
    IF ok THEN ok := sqlite3_step(stmt) = SQLiteDone END;
    IF stmt # NIL THEN
      IF sqlite3_finalize(stmt) # SQLiteOk THEN ok := FALSE END;
      stmt := NIL
    END;

    IF ok THEN
      rc := sqlite3_prepare_v3(db, buf, -1, 0, stmt, tail2);
      ok := (rc = SQLiteOk) AND (stmt # NIL);
      IF ok THEN ok := sqlite3_step(stmt) = SQLiteRow END;
      IF ok THEN ok := sqlite3_column_int(stmt, 0) = 2 END;
      IF ok THEN ok := sqlite3_step(stmt) = SQLiteDone END;
      IF stmt # NIL THEN
        IF sqlite3_finalize(stmt) # SQLiteOk THEN ok := FALSE END;
        stmt := NIL
      END
    END
  END;

  IF stmt # NIL THEN
    IF sqlite3_finalize(stmt) # SQLiteOk THEN ok := FALSE END
  END;
  IF db # NIL THEN
    IF sqlite3_close(db) # SQLiteOk THEN ok := FALSE END
  END;
  IF ok THEN ExitCode := 42 END
END SQLitePrepareTail.